This invention relates to an automatic assembly machine having a multiplicity of assembling heads.
In an automatic assembly machine for assembling electronic parts on a printed circuit board by inserting the leads of parts into the holes of printed circuit board, electronic parts having a wide variety of shapes and dimensions must be assembled at predetermined positions on the printed circuit board. In order to assemble as many of such parts as possible by means of a single automatic assembly machine, the machine is required to have multiple assembling heads which are matched to the shapes and dimensions of the various parts.
In an automatic assembly machine of the typed described above it is necessary to select an assembling head from the multiplicity of heads available, and to effect control in such a manner that a position on the printed circuit board at which an electronic part is to be assembled is moved to the position of the selected assembling head. In the prior art the assembling heads are moved or indexed to the predetermined positions, the printed circuit board is placed on a table which has an origin and which is movable in the X- and Y-directions relative to the selected assembling head, and the table is moved under the control of a numerical control device or the like to the positions of the assembling positions so that the electronic parts can be assembled on the printed circuit board. With this method, however, a drive source is necessary to move or to index the assembling heads, as well as a drive source for moving the table. Furthermore, the assembling heads must be positioned at the predetermined locations in a highly accurate manner.
When multiple spindle heads are driven independently of one another using a common driving source, the known arrangement provides clutches for each of the heads and actuates the clutches by means of a solenoid or air cylinder. Such an arrangement is not only complicated in structure but high in cost owing to the provision of the clutches.